Medication dispensing balloon catheter

ABSTRACT

An inflatable medical device for the delivery of medications to an organ in the body including a catheter having a plurality of lumens disposed therein. The distal end of the catheter is adapted to be disposed within a bodily organ. A hollow, inflatable, medication-deliverable balloon is disposed on the distal end of the catheter and the interior of the balloon is in fluid flow relationship with one of the lumens to enable the balloon to be inflated. An array of conduits is disposed within the walls of the balloon for the delivery of medications to predetermined locations within said bodily organ. Another lumen in the catheter shaft is provided to deliver medications to the conduits in the wall of the balloon and an egress for the medications so that they may be dispensed at the site being treated.

BACKGROUND OF THE INVENTION

The present invention relates to a balloon that can dispense medicationsin a predetermined location within a bodily organ and especially relatesto a balloon catheter which can simultaneously provide forcibleexpansion of the cross section of a coronary artery that has beennarrowed by atherosclerotic lesion or stenosis and also dispense amedication to the site that has been forcibly expanded. In particular,the medication dispensing balloon of the present invention is disposedat the distal end of a catheter shaft having a plurality of lumenstherein. The balloon not only forcibly expands the cross section of thecoronary artery but also can simultaneously deliver a dosage ofmedication at the site of the expansion thereby to avoid injecting largequantities of the medications intravenously when only a small site needsto be treated. Moreover, the present invention relates to a inflatablemedical device in which the wall of the balloon serves both as thecontainment mechanism for the inflation fluid and also as the dispensingvehicle for medications.

DESCRIPTION OF THE PRIOR ART

Balloon catheters for expanding atherosclerotic lesions or stenosisesare well known in the art. Such devices include an inflatable balloondisposed at the end of a multi-lumen catheter shaft in which apressurizing fluid is forced into the balloon to expand it and theexpansion of the balloon engages the surface of the artery to enlargeits cross section. Such balloons, however, have not provided a means todispense medications at the site of the lesion or stenosis but ratherhave relied upon either injecting massive doses of drugs intravenouslyor withdrawal of the balloon catheter and reinsertion of anothercatheter into the patient's arterial system to administer themedication.

The U.S. Pat. No. 5,049,132 to Shaffer et al describes a doubled walledballoon catheter in which one balloon is inflated to enlarge the arteryand a circumferentially disposed second balloon is filled with amedication. The inside balloon is aperture-free and is mounted on acatheter shaft and receives inflation media from an inflation lumen inthe catheter shaft. A second lumen is spaced from the first lumen and iscarried by the catheter shaft also. A second balloon as mounted on thecatheter shaft in communication with the second lumen and a large numberof tiny apertures are formed in it. Upon application of significantpressure, the medications will flow through the apertures therebyproviding for the administration of controlled quantities of medication.As is apparent, the construction of double walled balloons and mountingthem on a catheter shaft is difficult and time consuming. Other examplesof double walled balloon catheters for the administration of medicationsare disclosed in the United States patent to Shockey et al, U.S. Pat.No. 4,994,033 which also provides an outermost sleeve with a pattern ofholes that are precisely controlled in their sizes. In the United Statespatent to Buras, U.S. Pat. No. 4,693,243, a flexible non-collapsibleconduit system is disclosed that is separably positioned about a cuffedendotracheal tube to allow for direct topical application of medicinalsubstances to tissues of the larynx which may be irritated by theendotracheal tube. An external injection port and tubing connect to theinternal passage of the endotracheal shaft to enable the topicalapplication of the medications while the shaft is in place within thelarynx or trachea.

SUMMARY OF THE INVENTION

According to the present invention I have discovered an inflatablemedical device for delivery of medications to an organ in the body inwhich a multi-luminal catheter shaft is disposed within a bodily organ,usual one of the arteries. An inflatable balloon is disposed at the endof the catheter shaft. The balloon is hollow and ismedication-deliverable by means of an array of conduits disposed withinthe wall of the balloon. A medication-deliverable lumen within thecatheter shaft is connected to the array of conduits by means of amanifold thereby to enable the balloon to dispense medications directlyon the site of the stenosis or lesion through apertures in the walls ofthe conduit or at the distal ends of the conduits. The conduitspreferably are radially arranged within the wall of the balloon and areindividually segregated so they are not in fluid flow relationship witheach other. With this radial arrangement and uniformly sized apertures,the medications can be dispensed evenly upon the diseased site beingtreated.

Quite importantly, the balloon of the present invention enables thephysician to control the rate of release of medications as desired,independently of the inflation pressure of the balloon. If the inflationmedia for the balloon is the medication to be dispensed, and if a singleballoon is used, the release rate of the medication is thus dependentupon the inflation pressure of the balloon. Lower pressures result inincomplete dilation and too high a pressure results in excessive drugrelease and even dissection of the organ in which it is disposed due tothe production of "water jets". With the balloon of the presentinvention, there is only a minimal increase in the profile of theballoon resulting from the presence of the conduits. Since multiplechannels exist in the balloon, it is possible to deliver more than onekind of drug without prior mixing and even simultaneous administrationof the medications. Also, since the balloons have a plurality ofconduits, some of the conduits can be used as heaters with the useelectric wires or some can provide heated fluids. The use of a multiplyconduited balloon is highly advantageous in that the walls of theballoon are integrally constructed with the conduits and thus there areno sealing surfaces to break nor welds to fail. The dispensing ofmedication is limited to predetermined locations thereby reducing theamount of medication necessary and therefore reducing side effectsthrough the use of large amounts of drugs.

In the manufacture of the balloon, a hollow tube of two or moredissimilar plastics material is co-extruded using conventional extrusiontechniques. A discrete phase, that is the phase which serves as theprecursor of the conduits and which dictates their location and shape,is formed of high density polyethylene, Nylon, low density polyethyleneor polyethylene copolymers. A continuous phase, that is the phase thatwill form the balloon with the discrete phase disposed therein, can beformed of polyethylene terapthalate or high density polyethylene. Highdensity polyethylene, low density polyethylene and polyethylenecopolymers can be extruded within polyethylene terapthalate and Nyloncan be extruded within high density polyethylene. After the phases areco-extruded, the discrete phase is withdrawn from the continuous phaseto leave the conduits inside the continuous phase. Co-extrusion of twoplastics materials is well known and conventional techniques are usedfor such processes. The essential criteria for matching of the twoplastics materials is that they not adhere to each other after extrusionand that the discrete phase can be withdraw from the continuous phaseand leave conduits in the continuous phase.

While co-extrusion is preferred to form the balloons, it is alsopossible to extrude tubes with the conduits already in them using knownextrusion dies. Because the precursors to the conduits are so narrow,normally between about 0.025 and 1.75 mm. within a tube having a wallthickness between about 0.1 and 2.5 mm. and outside diameter betweenabout 0.25 and 6.25 mm., I have found that extrusion with preformedconduits is not always satisfactory and that co-extrusion is best.

Following the extrusion of the conduited tube and the withdrawal of thediscrete phase, the medication dispensing balloon of the presentinvention can be formed by heating the tube to a predeterminedtemperature in a predetermined location (which determines the length ofthe balloon) while applying pressure to the interior of the tube. Thetube will inflate to form the balloon with the conduits formed withinthe walls of the balloon. After the balloon has been formed it can beattached to a multi-luminal catheter shaft and then folded for use.

The many other objects, features and advantages of the present inventionwill become apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a conduited medical balloonaccording the present invention. In this view the balloon is inflatedand a portion of the balloon is cut away to show the interior of theballoon.

FIGS. 1A and 1B are cross-sectional views taken along the lines 1A--1Aand 1B--1B respectively showing the lumens of the catheter shaft and theattachment between the catheter shaft and the balloon.

FIGS. 2A to 2H are cross-sectional views taken along the lines 2--2 ofFIG. 1 and show various embodiments of the conduiting within the wall ofthe balloon. FIGS. 2B, 2D, 2F and 2H are exploded fragmentary views ofthe embodiments shown in FIGS. 2A, 2C, 2E and 2G respectively.

FIG. 3B is a side elevational view of another embodiment of the presentinvention for delivering medications to predetermined locations. FIG. 3Ais an end elevational view, partially in cross section, taken along thelines of 3A--3A of FIG. 3B.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

Referring to the drawings, a balloon-type catheter is shown. Theballoon-type catheter of the present invention is similar to othercatheters used for treating coronary artery disease except as otherwiseshown and described. As is conventional, the catheter is attached to anarray of hubs (not shown) being typically made of rigid materials. Thesehubs are utilized for the introduction of inflation fluids, medicationsand the disposition of a guide wire as will be described hereinafter.The hubs are attached to the proximal end of a multi-luminal tubing 14,as is conventional. A medical balloon 16 is positioned at the distal endof the catheter shaft 14. Medical balloon 16 is made of the materialsdescribed herein and is heat sealed or adhesively attached (as isconventional) at its respective ends 16a and 16b to catheter shaft 14. Acollar 27a is fitted around the distal end 16b of the balloon 16 andaffixed thereto to hold the balloon 16 in place on the shaft 14. Aninflation port 20 is formed in an inflation lumen 22 (shown in FIGS.2A-2H). The port 20 provides communication between the interior of theballoon 16 and the inflation lumen 22. Lumen 22 also communicates withany desired source of compressed inflation fluid at the hub mentionedabove as is conventional for balloon catheters.

A medication lumen 28 is provided within catheter shaft 14. Lumen 28extends completely through the catheter and communicates with amedication injection port 29 at the proximal end of the catheter shaft14. Aperture 29 is disposed within a manifold 27 (that is attached toboth the balloon 16 and the shaft 14) and is in fluid flow communicationwith medication dispensing conduits 40 disposed within the balloon aswill be described hereinafter.

A third lumen 13 extends completely through the catheter shaft 14 sothat a conventional guidewire 15 with a conventional exploratory tip 15amay be inserted in balloon 13 to assist in catheter insertion in aconventional manner.

As mentioned previously lumen 28 is in fluid flow communication with anopening 29 that is disposed within manifold 27. Manifold 27 is in fluidflow communication with an array of conduits 40 disposed within the wallof balloon 16. In the preferred embodiments these conduits are radiallyarranged within the perimeter of wall 16, as best shown in FIGS. 2A-2H.

In the embodiment shown in FIG. 1, each of the conduits 40 is providedwith an aperture 17 for the introduction of medication into the bodilyorgan that has been catheterized. While the Figure shows a helical arrayof apertures 17, any configuration that enables the introduction ofmedications can be used. The apertures 17 are easily formed in theconduits 40 by inflating both the balloon 16 and the conduits 40 withair and then pricking each conduit wall lightly with a pin until it isdeflated or the conduits 40 can be pierced with laser irradiation. Theapertures 17 preferably have openings of predetermined sizes in therange of 0.0025 to 2.5 mm. depending upon the viscosity of themedication being dispensed and the desired flow rate. On the other handelongated slits on the outside of the conduit can be used also, ifrequired. The preferred shape of the apertures is round, but oval,square and rectangular shapes have applicability.

Variously shaped conduits 40 can be made, as depicted in FIGS. 2A to 2H.In FIGS. 2A and 2B a balloon 16 is shown having a uniform wall thicknesswith generally rectangular conduits 40 formed therein. The conduits 40will contain the medication to be dispensed in the bodily organ beingtreated. The wall thickness of the balloon 16 can be between about 0.005and 0.25 mm. with the conduits 40 each having a width and height betweenabout 0.075 and 6.25 mm. The wall thickness between the conduits 40 andthe wall thickness between the conduit 40 and the exterior of theballoon 16 can be between about 0.0025 and 0.125 mm.

In the embodiment shown in FIG. 2C, the conduit 40, as depicted, ismerely a slit before being inflated with a medication. When the conduit40 is filled with medication it can be enlarged significantly frominflation. The conduits can be spaced from each other by ribs 16d andthe wall thicknesses can be similar.

In FIGS. 2E and 2F another embodiment is shown in which the conduits 40have a generally ovoid shape with the ribs 16d having a lesser widththan the width of the conduits 40. In FIGS. 2G and 2H the conduits 40again have a ovoid shape with the internal wall of the balloon 16 havinga generally cylindrical shape and the exterior wall being formed withthe ribs 16d spacing them apart.

In each of the embodiments shown in FIGS. 2A to 2H, the catheter shaft14 extends entirely through the length of the balloon 16. The lumen 13has the guidewire 15 and lumen 28 is used for the introduction ofmedications. An opening 20 is formed in lumen 22 to introduce expansionfluids into the balloon 20 to enable the balloon to be inflated at thesite of the surgical treatment.

In FIG. 3A a balloon similar to that of FIG. 1 is shown. The medication,however, rather than be introduced through apertures 17 disposed withinthe balloon 16 are introduced through directly from the ends of theconduits 40. The distal end of the balloon 16 is attached to thecatheter shaft 14 and the ends 40a of the conduits 40 empty directlyfrom them. A ring 41 can be fitted around and attached to the distal endof the balloon 16 to aid in the construction.

It is apparent that modifications and changes can be made within thespirit and scope of the present invention but it is my intention,however, only to be limited by the scope of the appended claims.

As my invention I claim:
 1. An inflatable medical device for thedelivery of medications to an organ in the body, said devicecomprising:a catheter having a plurality of lumens disposed therein,said catheter having a distal end adapted to be disposed within a bodilyorgan; a hollow, inflatable, medication-deliverable balloon defined bywalls and having a distal and a proximal end, the proximal end of theballoon being disposed on the distal end of said catheter, the interiorof said balloon being in fluid flow relationship with one of said lumenswhereby to provide the interior of said balloon with inflation fluids; aleast one conduit for the delivery of medications to predeterminedlocations within said bodily organ, said conduit being disposed withinthe wall of said balloon; means for delivering medications from anotherof said lumens in said catheter to said conduit; means for dispensingmedications from said conduit to said predetermined locations.
 2. Thedevice according to claim 1 wherein there is an array of radial arrangedconduits disposed within said balloon, said conduits being spaced fromeach other within the walls of said balloon and individually segregatedfrom each other so as not to be in fluid flow relationship with eachother.
 3. The medical device according to claim 2 wherein said conduitsare uniformly arrayed and spaced from each other around said balloon. 4.The medical device according to claim 2 wherein said conduits areimperforate over their lengths and terminate in dispensing meansdisposed at the distal end of said balloon whereby to provide egress formedications from said conduits.
 5. The medical device according to claim2 wherein said balloon and said conduits are of a unitary construction,said conduits being co-extruded in said balloon.
 6. The medical deviceaccording to claim 1 wherein the dispensing means are disposed on theouter surfaces of said conduits.
 7. The medical device according toclaim 6 wherein said dispensing means includes perforations on saidconduits.
 8. An inflatable medical device for intervascular delivery ofmedications, said device comprising:an inflatable balloon defined bywalls and adapted to receive inflation fluids; an array of conduitsdisposed within the walls of said balloon, said conduits extendingsubstantially the entire length of said balloon, said conduits beingadapted to deliver medications to predetermined locations within abodily organ; means to inflate said balloon and means to delivermedications to said to said conduits; means to dispense medications fromsaid conduits to said bodily organ;
 9. The medical device according toclaim 8 wherein said conduits are arranged around said balloon, saidconduits being spaced from each other on said balloon and individuallysegmented from each other so as not to be in fluid flow relationshipwith each other.
 10. The medical device according to claim 8 whereinsaid dispensing means are disposed on the outer surfaces of each of saidconduits.
 11. The medical device according to claim 10 wherein saiddispensing means includes perforations on said conduits.
 12. The medicaldevice according to claim 8 wherein said conduits are imperforate overtheir lengths and terminate in apertures disposed at distal ends thereofwhereby to provide egress for medications from said balloon.
 13. Themedical device according to claim 8 wherein said balloon and saidconduits are of a unitary construction, said conduits being co-extrudedin said balloon.